1. Field of the Invention
This invention relates to the field of lipidic furans, and more particularly to the use of certain lipidic furans characterized by an aliphatic hydrocarbon-chain with a minimum of nine carbon atoms, attached to the number two position on a furan ring, in combination with retinol palmitate, for improving the condition of human skin.
2. Description of Prior Art
For many years, there has been much folklore surrounding the beneficial qualities of avocados and avocado oil in improving the skin.
It has been observed that workers handling avocado oil have significantly moisturized, smoother appearing hands. It has also been observed that a group of Central American Indians, whose diet included a high proportion of fresh avocados and avocados in a slightly warmed decoction, had significantly healthier looking skin than tribes in nearby areas that did not include avocado in their diets in significant proportions.
Some skin care specialists recommend placing packs of freshly mashed avocado pulp to the skin, as well as various preparations containing avocado and avocado oils to freshen and revitalize the skin and improve its appearance.
Over the years, there have been attempts to determine exactly what it is in the avocado which improves the appearance of the skin. However, these efforts have been unsuccessful.
In U.S. Pat. No. 4,386,067 to Guillon, the non-saponifiable fraction of avocado oil was mixed with the non-saponifiable fraction of soya-bean oil to form a mixture which aids in moisturizing the upper layer of skin. However, Guillon states that the composition of the non-saponifiable fraction is complex and is not completely known. No reference to lipidic furans is made.
U.S. Pat. No. 4,324,802 to Koulbanis et al. discloses that the non-saponifiable fractions of avocado oil and/or soy bean oil have useful dermatological properties for use in cosmetic compositions to improve the appearance of aging, dry or wrinkled skin. Again, however, the composition of the non-saponifiable fractions of the avocado oil is not identified.
In the journal article "New Compounds From Avocado Pear", by Y. Kashman, 1. Neeman and A. Liftshitz, Tetrahedron Vol. 25, pp. 4617-4631, compounds of Structure I, II and III with molecular weights 246, 248 and 250 were disclosed. No mention was made of the use of these compounds.
In the journal article "Partial Isolation Of and Characterization Of A New Natural Inhibitor Of Lysyl Oxidase From Avocado Seed Oil", by Mr. J. Werman, S. Mokady, and I. Neeman, J. Agric. Food Chem. 1990, 38, 2164-2168, it was reported that a unsaponifiable component ("C") of avocado seed oil inhibits the action of lysyl oxidase. Lysyl oxidase initiates cross-links in collagen and in collagenic connective tissue, including skin, and an over abundance of these crosslinks results in wrinkles, and a lack of elasticity in the skin. Werman et al. noted component "C" was derivable only from the unsaponifiable fraction of unrefined avocado oil or avocado seed oil. The researchers were unable to determine the composition of component "C", which was stated as being "probably a mixture of some polyalcoholic compounds, one of them having a molecular weight of 248 and being composed of a 17-carbon aliphatic chain with a furan ring." p. 2167
In "The Avocatins--A New Class of Natural Products" by H. Magalhaes Alves, et al., An. Acad. brasil, Cieno, (1970), 42 (suplemento), compounds referred to as avocatins were discussed. These compounds are extractable from seeds of avocado pears, and have structures including the following alkyl furans:
furan (2)--(CH.sub.2)--CH.dbd.CH.sub.2, furan (2)--(CH.sub.2).sub.11 C.tbd.CH PA0 furan (2)--CH.dbd.CH--(CH.sub.2).sub.9 --CH.dbd.CH.sub.2, PA0 furan (2)--CH.sub.2 --CH.dbd.CH--(CH.sub.2).sub.8 CH.dbd.CH.sub.2 PA0 X=CH.sub.3 or COOCH.sub.3 PA0 y=number of methylene groups PA0 Capric furan (2 Furanyl nonane) PA0 Lauric furan (2 Furanyl hendecane) PA0 Myristic furan (2 Furanyl tridecane) PA0 Margaric furan (2 Furanyl hexadecane) PA0 Arachidic furan (2 Furanyl nonadecane) PA0 Lignoceric furan (2 Furanyl docosane) PA0 Lauroleic furan (11-(2 Furanyl)-8-cis-hendecene) PA0 Palmitoleic furan (15-(2 furanyl)-8-cis-pentadecene) PA0 Cis-vaccenic furan (17-(2 furanyl)-10-cis-heptadecene) PA0 Erucic furan (21-(2 furanyl)-12-cis-heneicosene) PA0 Nervonic furan (23-(2 furanyl)-14-cis-trieicosene) PA0 Linoleic furan (17-(2 furanyl)-8-11-cis-cis-heptadecadiene) PA0 Arachidonic furan (19-(2 furanyl)-4-7-10-13-cis-cis-cis-cis-nonatetraene) PA0 Crepenynic furan (18-(2 furanyl)-octadec-cis-8-en-11-yl) PA0 No treatment PA0 Control Vehicle--oil-in-water emulsion PA0 Vehicle with 3% (w/w)* natural isolated Linoleic Furan PA0 Vehicle with 3% (w/w) synthetic Linoleic Furan PA0 Control (untreated PA0 Control vehicle PA0 Vehicle+2% Linoleic Furan PA0 Untreated Control PA0 Control vehicle PA0 Vehicle+1% (w/w) Natural Linoleic Furan PA0 Vehicle+2% (w/w) Natural Linoleic Furan PA0 Vehicle+3% (w/w) Natural Linoleic Furan
Each of these alkyl furans of the Alves, et al., article have a 13 carbon alkyl chain having one or two double bonds, or a single triple bond. The chain is attached to the number two position of a furan ring.
The short communication entitled "Isolation And Structure Elucidation of Growth Inhibitors For Silkworm Larvae From Avocado Leaves" by Ching-Fun Chang, et al., Agr. Biol. Chem., 39 (5), 1167.about.1168, 1975 discloses a growth inhibitor for Silkworm larvae, C.sub.23 H.sub.C40 O.sub.4 which when treated with p-toluene sulfonic acid, yielded a new compound C.sub.21 H.sub.34 O,MW302, which is a two-substituted furan. The Chang et al. article fails to disclose the exact structure of this molecule or any cosmetic or therapeutic use of the compound for human skin use.
The journal article "A New Lipid Component Identified in Avocado Pear by GC-MS and NMR Spectroscopy", by N. Frega, et al. This journal article discloses the discovery of a new cyclic lipic compounds in the extracts of the unsaponifiable extracts of avocado having the following structure: ##STR1##
Not only is this compound not a furanyl lipid, but there was no discussion of for what these compounds might be useful.
Lastly, the article "Fatty Acids, Part XVI: The Synthesis Of All Isomeric C.sub.18 Furan-Containing Fatty Acids", by M. S. F. Lie Ken Jie and C. H. Lam, Chemistry and Physics of Lipids 21 (1978) 275-287, discloses, as an intermediate in the synthesis of two and five substituted furanic compounds, the following structure: EQU CH.dbd.CH(CH.sub.2).sub.y X,
However, there is no discussion of what these compounds might be useful for.
Although a substantial amount of effort has been directed to elucidate what it is in avocados which make avocados good for the skin, these efforts have fallen short. No one in the past has identified the specific compounds from avocado which have useful cosmetic and therapeutic effects.